MCB 150 Study Set Post Adaptive Follow ups EXAM 1
Imagine a beaker with solutions separated by a lipid bilayer (like what is shown in Figure 6.12, step 3). Predict what will happen after addition of a new solute to the solution on the left side, if the new solute (1) crosses the lipid bilayer readily or (2) is incapable of crossing it. See Section 6.3 (Page 128) .
(1) The new solute will diffuse from left to right to establish equilibrium. (2) The water level on the right will fall.
Polymers that contain sugars ...
(a), (b), and (c). (a)=may store hereditary information. (b)=may store energy. (c)=may protect cells.
Based on the sequences from the same section of DNA below, which two species would be closest on a phylogenetic tree? Species A: AACTAGCGCGAT Species B: AACTAGCGCCAT Species C: TTCTAGCGGTAT (See Section 1.5 (Page 7) ).
A and B
Which statement best explains the energy transformation that occurs when methane reacts with oxygen to produce carbon dioxide and water (CH4 + 2 O2—→ CO2 + 2 H2O)? See Section 2.3 (Page 68) .
A decrease in potential energy from reactants to products is released as heat.
The catalytic activity of PAH also requires a coenzyme that is oxidized in the reaction. This coenzyme is then subsequently reduced by NADH to regenerate it for additional PAH reactions. If a person were diagnosed with a novel form of PKU, in which the PAH enzyme was fully functional, what defects would you look for to explain the accumulation of phenylalanine?
A defect in the reactions with NADH. A defect in the production of the coenzyme.
Consider the two-step metabolic pathway: A—(enzyme 1)—>B—(enzyme 2)—>C How would inactivating enzyme 1 affect the concentrations of molecules A, B, and C relative to what they would be if the pathway were fully functional? See Section 8.5 (Page 185) .
A would increase; B and C would decrease.
In many animal cells, the uptake of glucose into the cell occurs by a cotransport mechanism, in which glucose is cotransported with Na+ ions. Complete the diagram below using the following steps. Drag the pink labels to the pink targets, indicating the relative concentration of glucose inside and outside the cell. Drag the correct white label to the white target, indicating the direction that Na+ ions and glucose move through the cotransporter. Drag the blue labels to complete the sentences on the right, indicating how Na+ ions and glucose move through the cotransporter relative to their electrochemical and concentration gradients.
A-(glucose) low B- glucose down, na+ down C-(glucose) high Na+ moves down its electrochemical gradient glucose moves against its concentration gradient
What would be the effect of abundant ATP on the citric acid cycle? See Section 9.4 (Page 198)
ATP binds at the allosteric regulatory site of the enzyme that combines acetyl CoA and oxaloacetate and slows the citric acid cycle.
How does the sodium-potassium pump work to transport sodium and potassium against their concentration gradient?
ATP hydrolysis provides the energy to transport ions against their concentration gradients.
What do cells do to activate nucleotides for incorporation into a polymer and why? See Section 4.1 (Page 95) .
Add phosphate groups to raise the potential energy of monomers.
What process below would speed up a reaction rate by decreasing the activation energy?
Adding a catalyst
Which of these is an example of negative feedback?
After you eat, insulin stimulates the lowering of blood sugar levels.
Make a concept map that relates the four levels of protein structure and shows how they can contribute to the formation of an active site. Label the diagram by dragging the labels to the appropriate targets.
Amino Acid Sequence Primary Structure R Groups Secondary Structure Alpha Helices Tertiary Structure Quatenary Structure Active Site
In proteins, secondary, tertiary, and quaternary levels of structure depend on primary structure. Which of the following most accurately lists elements of any protein's primary, secondary, tertiary, and quaternary structure, in that order? See Section 3.2 (Page 84) .
Amino acid sequence, hydrogen bonding between backbone groups, overall shape of a single polypeptide, and combinations of tertiary structures
Which class of amino acids contains side chains that would be unable to form hydrogen bonds with water? See Section 3.1 (Page 80) .
Amino acids with nonpolar side chains
Which of the following is true of cell membranes?
Amphipathic proteins can span the membrane.
What is responsible for this change in taste?
Amylase breaks down the starch in the cracker into glucose monomers, which stimulate the sweet receptors in your tongue
What is the major difference between amylose and amylopectin?
Amylose is a straight-chain polymer of glucose, whereas amylopectin is highly branched.
Both starch and cellulose are glucose polymers. Why can animals easily degrade starch, but not cellulose?
Animals have the enzymes to degrade a-1,4-glycosidic bonds, but not b-1,4-glycosidic bonds.
Which of the following can change the shape of an enzyme? See Section 8.4 (Page 183) .
Answer is all of the above -temperature -phosphorylation -pH
Which domains include prokaryotes?
Archaea and Bacteria
In graphs of enzyme activity versus temperature, activity increases up to a certain temperature and then decreases again. What is the mechanism that explains this pattern?
As temperatures increase, substrates collide with the enzyme more, but even higher temperatures cause too much enzyme movement and the enzyme denatures.
Which is true of the metabolic pathway shown here? See Section 8.5 (Page 185) . enzyme 1 enzyme 2 enzyme 3 A ————————> B ————————> C ————————> D
B is the product of enzyme 1 and the substrate for enzyme 2.
In step 3 of the citric acid cycle, the enzyme isocitrate dehydrogenase is regulated by NADH. Compare and contrast the regulation of this enzyme with the regulation of phosphofructokinase in glycolysis. Drag the terms on the left to the appropriate blanks on the right to complete the sentences.
Both phosphofructokinase and isocitrate dehydrogenase are regulated by feedback inhibition, where the product of the reaction or series of reactions inhibits the enzyme activity. They differ in that phosphofructokinase is regulated by allosteric inhibition while isocitrate dehydrogenase is controlled by competitive inhibition.
Activity: Active Transport Which of the following statements is TRUE with regard to this animation?
Both sodium and potassium ions are transported against their concentration gradients.
What molecule produced during the citric acid cycle feeds into the electron transport chain? See Section 9.4 (Page 198) .
FADH2
In terms of structure, how do channel proteins differ from carrier proteins? Drag the appropriate items to their respective bins.
Channel Proteins- form pores in the membrane are open or close in response to a signal have different functional groups in the interior of the pore that function as a molecular filter Carrier Proteins- change shape to shuttle molecules or ions across the membrane undergo conformational changes caused by the binding of the specific molecules
In 1951, Erwin Chargaff was accumulating data on the molar ratios of nucleotides using DNA obtained from a variety of sources. Watson and Crick met with Chargaff to discuss his work in 1952. Explain how Chargaff's observations helped Watson and Crick to propose the complementary base pairing in their model of double-stranded DNA. Would you expect similar ratios of nucleotides if Chargaff had used RNA instead? Explain why or why not.
Chargaff's data show that an approximately 1:1 molar ratio exists between adenine and thymine bases, and between guanine and cytosine bases. Watson and Crick used these data to come up with complementary base pairing, which requires that every adenine pairs with a thymine and every guanine pairs with a cytosine. In RNA, Chargaff's rules do not apply since RNA is single-stranded and the pairing is not consistent throughout the molecule.
Which of the following statements accurately compares the different polysaccharides?
Chitin, cellulose, and peptidoglycan consist of long, parallel strands linked to one another.
Which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not? See Section 6.1 (Page 121) .
Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic.
Which answer correctly associates a process in cellular respiration with (1) what goes in and (2) what comes out? See Section 9.1 (Page 191) .
Citric acid cycle: (1) Acetyl CoA; (2) NADH, ATP, FADH2,, and CO2
What does Figure 1.5 indicate about the relationships among domain Bacteria, domain Archaea, and domain Eukarya?
Domain Archaea and domain Eukarya are more closely related to each other than either is to domain Bacteria.
In what important way does competitive inhibition differ from allosteric inhibition?
During competitive inhibition, a regulatory molecule binds to the active site, whereas during allosteric inhibition, a regulatory molecule binds to a site other than the active site.
Which statement best describes results of an experiment designed to test whether the protein cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel?
Electric current flowed only in the presence of CFTR, indicating the movement of chloride ions.
Which statement most accurately describes the relative potential energies (P.E.) of the electrons in the following molecules: H2, O2, and H2O? See Section 2.3 (Page 68) .
Electrons in H2 and O2 have relatively high P.E; electrons in H2O have relatively low P.E.
In a metabolic pathway, A is converted to B via enzyme one, B to C via enzyme two, and C to D via enzyme three. According to the retro-evolution hypothesis for metabolic pathway evolution, which enzyme evolved first?
Enzyme three
Which of the following is true of enzyme phosphorylation?
Enzymes catalyze phosphorylation.
Which of the following statements best describes the major difference between prokaryotes and eukaryotes?
Eukaryotic cells have a membrane-bound nucleus; prokaryotic cells do not.
Which statement most accurately describes how the structures of fats, steroids, and phospholipids compare? See Section 6.1 (Page 121) .
Fats and phospholipids contain glycerol whereas steroids do not.
Which of the following was evidence for the fluid mosaic model of membrane structure?
Freeze fracture followed by scanning electron microscopy showed pits and mounds.
In the same portion of DNA, you find the following sequences: Land Plants: ATATCGAG Green Algae: ATATGGAG Fungi: ATATGGAC Based on these data, which statement most accurately summarizes the evolutionary relationships of these three types of organisms? See Section 1.5 (Page 7) .
Fungi are more closely related to green algae than to land plants.
How is genetic information preserved during the copying of DNA? See Section 1.4 (Page 6) .
Genetic information is preserved by the connections that occur between A and T and G and C in the two strands of the double helix.
What is an important function of glycoproteins in animal cells?
Glycoproteins are important in cell-cell recognition.
The total energy in a molecule, its enthalpy, is given by the letter ____. See Section 8.1 (Page 173) .
H
If the researchers had compared vines growing under variable light conditions, how might this have changed their interpretation of the data?
If different vines were exposed to different light levels, this would add another variable to the study. Under these varying conditions, changes in the herbivory index might be due to light availability.
How do high temperatures speed chemical reactions?
Heat causes the reactants to move faster and collide more often.
Under which conditions will the citric acid cycle be activated?
High levels of AMP
An industrial process called hydrogenation is used to convert vegetable oil into a semisolid compound called margarine. Explain why hydrogenation is an appropriate term for this process. Drag the terms on the left to the appropriate blanks on the right to complete the sentences.
Hydrogenation is used because the process is likely to involve converting C=C bonds into C−C bonds by adding hydrogens. Fats with only C−C bonds (i.e., saturated) tend to be semisolid at room temperature.
Nonpolar amino acid residues are typically found in the interior of globular proteins like chymotrypsin (Fig. 3.8d). Which chemical force is most directly responsible? See Section 3.2 (Page 84) .
Hydrophobic interactions
Figure 6.18: Freeze-Fracture Preparations Allow Biologists to View Membrane Proteins For the study shown in the figure, what is the most appropriate control to show that the observed pits and mounds are not simply irregularities in the lipid bilayer caused by the freeze-fracture process? See Section 6.4 (Page 131) .
Instead of a cell, use an artificial membrane composed only of pure phospholipids.
Which answer most accurately summarizes the (1) structural and (2) functional properties of actin filaments, intermediate filaments, or microtubules? See Section 7.6 (Page 163) .
Intermediate filaments: (1) many subunit types; (2) one cellular role
An acid is defined by which of the following?
It donates protons to other substances in a solution.
Which of the following is true of the peptide bond?
It is a covalent bond formed via a condensation reaction.
Which statement accurately summarizes a feature of passive transport? See Section 6.4 (Page 131) .
It is a spontaneous process.
Which of the following is true of glycolysis?
It leads to the reduction of NAD+.
Phenylalanine is required for the production of many of your proteins, but none of your cells are capable of synthesizing this amino acid. What type of metabolic pathway must be responsible for providing this essential amino acid to your cells?
It must be obtained by breaking down proteins into amino acids, which would include phenylalanine.
Suppose a cell is placed in a solution with a high concentration of potassium and no sodium. How would the cellular sodium-potassium pump function in this environment?
It would continue using ATP to pump sodium out of the cell and potassium into the cell.
The first reaction in the catabolism of phenylalanine uses the enzyme phenylalanine hydroxylase (PAH) to convert phenylalanine into tyrosine, a different amino acid. PKU results from defects in this enzyme. It has been hypothesized that phenylalanine is both the substrate and an allosteric regulatory molecule for PAH. There are two models, one of them shows how PAH would appear if the phenylalanine concentration is low (inactive enzyme), another shows how PAH would appear if the phenylalanine concentration is high (active enzyme). Label phenylalanine, the allosteric binding site, and the active site. Drag the appropriate labels to their respective targets.
Left side top: The phenylalanine concentration is low Left Side Middle: the allosteric binding site Left Side Bottom: the phenylalanine concentration is high The right side top: phenylalanine The right side bottom: The active Site
If ATP hydrolysis took place in an acidic solution such that it no longer carried negative charges, how would you predict that the free energy released would change?
Less free energy will be released.
Based on the data shown in Figure 1.8, at approximately what height do male and female giraffes spend most of their time feeding? See Section 1.6 (Page 10) .
Males: 3m; Females: 2.5m
Colorful animal cells are rich in melanosomes, a specialized organelle that contains pigments, like melanin, and the enzymes that produce them. Melanosomes are found only in certain cells and are called lysosome-related organelles based on their origin, but they do not contain hydrolases or have a low pH. How would you expect these melanosomes to form?
Melanosomes originate from the endomembrane system and receive enzymes imported from the Golgi apparatus.
Considering the reaction CH4 (methane) plus O2 yields CO2 plus H2O plus energy, which of the following is true?
Methane acts as an electron donor.
Which of the following is true of NADH and FADH2?
NADH has more potential energy than FADH2.
Which statement correctly describes one aspect of the precise bonding between components of a nucleotide?
Nitrogen in the nitrogenous base bonds to the 1′ carbon of sugar.
Can an enzyme make a nonspontaneous reaction occur spontaneously? Why or why not? See Section 8.3 (Page 180) .
No, because enzymes do not affect the overall ΔG of a reaction.
Figure 6.21: Electric Current Measurements Indicate That Chloride Flows through CFTR In the experiment shown in Figure 6.21, the researchers repeated the "with CFTR" treatment 45 times, but recorded current in only 35 of the replicates. Does this observation negate the conclusion? Why or why not? See Section 6.4 (Page 131) .
No. Observation of current in a large fraction of the "with CFTR" replicates provides strong evidence for the chloride channel hypothesis.
How do fats differ from proteins, nucleic acids and polysaccharides? See Section 6.1 (Page 121) .
Only fats do not form from the polymerization of monomers.
Review the experiment shown in Figure 5.7. How would the results change if sperm attachment required only the protein portion of egg glycoproteins? See Section 5.3 (Page 114) .
Only intact glycoprotein and pure protein would exhibit significant attachment inhibition compared to the untreated control.
During the denaturation of ribonuclease, which level of protein structure was maintained?
Only the primary protein structure was maintained.
Which of the following statements is most likely to be true in the case of the feedback-regulated enzymatic pathway shown?
P4 binds E1 and deactivates it.
What is the difference between peptidoglycans, found in the cell walls of prokaryotes, and chitin, found in the exoskeletons of insects?
Parallel strands of glucosamines in chitin are cross-linked by hydrogen bonds, whereas parallel strands of peptidoglycan are linked by peptide bonds.
Membrane Transport (2 of 4): The Sodium-Potassium Pump (BioFlix tutorial) Part A:All cells contain ion pumps that use the energy of ATP hydrolysis to pump ions across the plasma membrane. These pumps create an electrochemical gradient across the plasma membrane that is used to power other processes at the plasma membrane, including some transport processes. In animal cells, the main ion pump is the sodium-potassium pump. Complete the diagram below using the following steps. Drag the correct white label to the white target, indicating how many ions move through the pump and in which directions. Drag the pink labels to the pink targets, indicating the relative concentrations of Na+ and K+ inside and outside the cell. Drag the blue labels to the blue targets, indicating the relative charges inside and outside the cell. Part B: Because ions carry a charge (positive or negative), their transport across a membrane is governed not only by concentration gradients across the membrane but also by differences in charge across the membrane (also referred to as membrane potential). Together, the concentration (chemical) gradient and the charge difference (electrical gradient) across the plasma membrane make up the electrochemical gradient. Consider the plasma membrane of an animal cell that contains a sodium-potassium pump as well as two non-gated (always open) ion channels: a Na+ channel and a K+ channel. The effect of the sodium-potassium pump on the concentrations of Na+ and K+ as well as the distribution of charge across the plasma membrane is indicated in the figure below. Which of the following statements correctly describe(s) the driving forces for diffusion of Na+ and K+ ions through their respective channels? Select all that apply.
Part A: A- 3 Na+ up, 2 K+ down B- Na+ high, K+ low C- excess + charge D- Na+ low, K+ high E- excess - charge Part B: The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. The electrochemical gradient is larger for Na+ than for K+.
Amino Acid Functional Groups Part A: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Drag each item to the appropriate bin. Part B: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Drag each item to the appropriate bin. Part C: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Drag each item to the appropriate bin.
Part A: Acidic-None Basic- Arginine Neutral Polar- Asparagine Neutral NonPolar- Alanine Part B: Acidic-None Basic- Lysine Neutral Polar- Serine Neutral NonPolar- Proline Part C: Acidic-Glutamic Acid Basic- None Neutral Polar- Threonine Neutral NonPolar- Tryptophan
Activity: Selective Permeability of Membranes Part A: Structure A in the figure is a(n) _____. Part B: Which of these cannot rapidly pass directly through the phospholipids of the plasma membrane?
Part A: transport protein Part B: B, C, and D
Chapter 7 Question 15 - Case Study Part A: Even without being exposed to sunlight, humans exhibit a wide range of skin colors due to differences in the abundance of melanosomes. A recent hypothesis to address this difference is that autophagy plays a role in these differences. What is autophagy? Part B: How might you expect this process to differ between individuals with darker skin and those with lighter skin?
Part A: Autophagy is the process of recycling damaged organelles and other cytoplasmic components by wrapping portions of the cytoplasm in a membrane and fusing it with lysosomes. Part B: Light-skinned individuals have a higher rate of autophagy in keratinocytes than dark-skinned individuals.
ATP and Energy Part A: Identifying the highest energy form of adenosine Select the highest energy form of adenosine from the following images. Part B: Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?
Part A: Orange Hexagon+pentagon, yellow hexagon, yellow box with 3P, 3=O (double bond), 5-O (single bond) Part B: γ-phosphate (the terminal phosphate)
Part A: Protein structure is often evaluated using enzymes like trypsin that cut the protein at specific amino acid residues exposed on the surface. The results from this type of experiment using PAH in the presence (+) or absence (−) of phenylalanine is shown below. Interpret the results in terms of the effect phenylalanine has on the structure of PAH. Part B: Do the results support the hypothesis that phenylalanine is an allosteric regulator?
Part A: PAH has a different structure in the presence of phenylalanine compared to when it is absent. This is shown by the different products generated after exposure to trypsin between the two conditions. Part B: These results support the hypothesis that phenylalanine is an allosteric regulatory molecule.
Tour of an Animal Cell: The Endomembrane System (BioFlix tutorial) Part A: The various parts of the endomembrane system serve different functions in the cell. In this activity, you will identify the roles of each part of the endomembrane system. Drag each function to the appropriate bin. Part B: All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes? Select all that apply Part C: Proteins that are secreted from a eukaryotic cell must first travel through the endomembrane system. Drag the labels onto the diagram to identify the path a secretory protein follows from synthesis to secretion. Not all labels will be used. Part D: Scientists can track the movement of proteins through the endomembrane system using an approach known as a pulse-chase experiment. This experiment involves the "pulse" phase: Cells are exposed to a high concentration of a radioactively labeled amino acid for a short period to tag proteins that are being synthesized. the "chase" phase: Any unincorporated radioactively labeled amino acids are washed away and large amounts of the same, but unlabeled, amino acid are added. Only those proteins synthesized during the brief pulse phase are radioactively tagged. These tagged proteins can be tracked through the chase period to determine their location in the cell. The data below were obtained from a pulse-chase experiment in which cells were examined at different times during the chase period. The numbers represent the radioactivity (measured in counts per minute) recorded at each of the indicated sites. The higher the number, the greater the radioactivity. Time ER Golgi Cytoplasm Lysosomes Extracellular space 3 minutes 162 7 21 5 4 20 minutes 73 88 17 10 8 60 minutes 9 35 14 112 13 120 minutes 11 23 18 151 10
Part A: Smooth ER-lipid synthesis, calcium ion storage, poison detoxification Rough ER- protein synthesis Golgi Apparatus-protein modification and sorting, cisternal maturation Lysosomes- macromolecule digestion, autophagy Part B: lysosomal enzyme insulin ER protein Part C: Protein synthessis--> A-Endoplasmic reticulum B- cis Golgi cisternae C- medial Golgi cisternae D- trans Golgi cisternae E- plasma membrane Part D: phagocytosis
Part A: Explain the lock-and-key model of enzyme activity Part B: What was incorrect about this model?
Part A: The shape of reactant molecules (the key) fits into the active site of an enzyme (the lock). Part B: Fischer's original model assumed that enzymes were rigid; in fact, enzymes are flexible and dynamic.
Chapter 7 Question 13 - Case Study Part A: The color of human skin is determined by the abundance of melanosomes in keratinocytes−the dominant cell type in skin. But keratinocytes do not produce melanosomes. Instead, less abundant melanosome factories called melanocytes make and secrete the organelles. How could keratinocytes take up these organelles? Select all that apply. Part B: What about this process must be altered to ensure the organelles remain in the keratinocytes?
Part A: from the extracellular space by receptor-mediated endocytosis from the extracellular space by phagocytosis Part B: inhibition of the fusion of the endosome and lysosome
Chapter 7 Question 8 Part A: Which features are common to all cells? Check all that apply. Part B: Which are specific to just prokaryotes, or just plants, or just animals? Drag the appropriate items to their respective bins.
Part A: genetic information (DNA) in chromosomes cytoskeleton the plasma membrane ribosomes the cytoplasm Part B: Plant Cell-chloroplasts, vacuoles Animal Cell-lack a cell wall, lysosomes Prokaryotic Cell-photosynthetic membranes, magnetite-containing structures, the nucleoid, flagella and fimbriae
Cellular Respiration (1 of 5): Inputs and Outputs (BioFlix tutorial) Part A: From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. Drag each compound to the appropriate bin. If the compound is not involved in glycolysis, drag it to the "not input or output" bin. Part B: In acetyl CoA formation, the carbon-containing compound from glycolysis is oxidized to produce acetyl CoA. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of acetyl CoA formation. Drag each compound to the appropriate bin. If a compound is not involved in acetyl CoA formation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of acetyl CoA formation are included.) Part C: In the citric acid cycle (also known as the Krebs cycle), acetyl CoA is completely oxidized. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of the citric acid cycle. Drag each compound to the appropriate bin. If a compound is not involved in the citric acid cycle, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of the citric acid cycle are included.) Part D: In the last stage of cellular respiration, oxidative phosphorylation, all of the reduced electron carriers produced in the previous stages are oxidized by oxygen via the electron transport chain. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of oxidative phosphorylation. Drag each compound to the appropriate bin. If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of oxidative phosphorylation are listed.) Part E: Each of the four stages of cellular respiration occurs in a specific location inside or outside the mitochondria. These locations permit precise regulation and partitioning of cellular resources to optimize the utilization of cellular energy. Match each stage of cellular respiration with the cellular location in which it occurs. Labels may be used once, more than once, or not at all.
Part A: net input-Glucose, ADP, NAD+ net output-Pyruvate, NADH, ATP not input or output- O2, CO2, Coenzyme A, Acetyl CoA Part B: net input- NAD+, Pyruvate, Coenzyme A net output-NADH, CO2, Acetyl CoA not input or output- O2, ATP, Glucose, ADP Part C: net input- NAD+, Acetyl CoA, ADP net output-NADH, CO2, Coenzyme A, ATP not input or output- O2, Glucose, pyruvate Part D: net input- O2, NADH, ADP net output- ATP, NAD+, Water not input or output- Glucose, pyruvate, Acetyl CoA, CO2, Coenzyme A Part E: Glycolysis-Cytosol Acetyl CoA Formation-Mitochondrial Matrix Citric acid cycle-mitochondrial matrix oxidative phosphorylation-inner mitochondrial membrane
How do current models of enzyme function differ from Fischer's lock-and-key model? See Section 8.3 (Page 180) .
Rather than enzymes being rigid, we now believe they undergo an induced fit upon substrate binding.
Making Models: Drawing Membranes Part A: Your classmate has drawn four membrane models to try to remember how the lipid bilayer is built. Help her to select the best model. Part B: Interpret the model. Drag "True" or "False" to the end of each statement. Part C: Which of the following models provides the best representation of facilitated diffusion via a "channel"? Part D: Four students have done a nice job drawing membrane models. The models are drawn at different scales to serve different purposes. Order the students' models from most magnified (enlarged) to least magnified. Part E: Which student's model does the best job of showing membrane structure? Part F: Which student's model does the best job of showing facilitated diffusion of a solute?
Part A: oooooooo IIIIIIIIIIIIIIII IIIIIIIIIIIIIIII ooooooo Part B: The blue ovals are hydrophobic. False The model is called a bilayer because there are two main types of molecules present, lipids and proteins. False The blue ovals represent phospholipid heads. True The many black lines represent amino acid tails. False The strings of little red dots represent carbohydrates. True This model shows membrane transport. False Part C: Has the green thing in the middle Part D: Rekik, Thomas, Zubia, Elsa Part E: Rekik Part F: Thomas
Math Practice: Generating a Regression Line for Biological Data Researchers studying a species of endangered bird were interested in whether a relationship exists between the number of eggs laid by the mother bird at one time and the proportion of chicks surviving to the following year. The data shown here were collected from 10 different nests in a wild population. Part A: Your first step is to plot the data. Which variable would you put on the x-axis, and which variable would you put on the y-axis? Part B: Which type of graph is best suited to this data? Part C: Now suppose you plotted the data using a graphing program. Your scatter plot would look similar to this. Each point represents the data collected from one nest. The line is called a regression line (also called a trend line or best-fit line). From looking at this scatter plot, what do you think the regression line represents? Part D: The equation of the regression line can be expressed in this format: y = mx + b. In this equation, m is the slope of the line and b is the y-intercept. When a graphing program plots a regression line, it carries out calculations with the raw data to determine the equation of the line. Which equation most closely approximates the regression line shown in the graph? (For practice approximating the equation of a line, try this activity.) Part E: The equation of a regression line can be used to calculate the value of y expected for a particular value of x. What would be the approximate survival rate for a nest with 5 eggs? Part F: A statistical measure of how closely data fit a linear relationship is called the correlation coefficient (r). The value of the correlation coefficient can range between -1 and 1. When r > 0, y and x are positively correlated (y becomes larger as x becomes larger). When r < 0, y and x are negatively correlated (y becomes smaller as x becomes larger). The closer r is to either extreme of the range (-1 or 1), the stronger the linear relationship between the variables. When r = 1, all data points fall on the regression line in a perfect positive correlation. When r = -1, all data points fall on the regression line in a perfect negative correlation. As the value of r approaches 0, the data points display more scatter, indicating a weaker linear relationship. When r = 0, the variables do not have a linear relationship. The correlation coefficient of the data on chick survival vs. clutch size is -0.93. How would you interpret that correlation coefficient? Part G: Suppose you analyzed the same type of data for a different species and found a correlation coefficient of -0.17. How would you describe the relationship between chick survival and clutch size for that species? Part H: What can you conclude from the graph? Select all that apply.
Part A: x-axis: clutch size y-axis: chick survival Part B: scatter plot Part C: It represents the straight line that fits most closely the trend in the data Part D: y = -0.14x + 1.2 Part E: 0.50 Part F: Chick survival and clutch size are strongly negatively correlated. Part G: Chick survival and clutch size are weakly negatively correlated. Part H: Large clutch size is strongly correlated with lower chick survival.
Chemistry Review - Lipids: Functions of Lipids Part A:What do fats, steroids, and waxes have in common? Part B: Dr. Haxton told one of his students, "To move in the bloodstream, fats need the help of phospholipids." What would a good student say?
Part A: (b) Low solubility in water. Part B: Yes. Nonpolar molecules aren't compatible with water.
Activity: Glycolysis Part A: How many NADH are produced by glycolysis? Part B: In glycolysis, ATP molecules are produced by _____. Part C: Which of these is NOT a product of glycolysis? Part D: In glycolysis, what starts the process of glucose oxidation? Part E: In glycolysis there is a net gain of _____ ATP.
Part A: 2 Part B: substrate-level phosphorylation Part C: FADH2 Part D: ATP Part E: 2
Activity: The Structure of ATP Part A:Which of these is ATP? Part B: What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?
Part A: 3 yellow P's, Orange ribose, 1 green A Part B: hydrolysis
Part A: Prokaryotic cells are found in the domain(s) _____. Part B: In the five-kingdom system, prokaryotes are placed in the kingdom _____. Part C: A human is classified in domain _____ and kingdom _____. Part D: A rose bush is classified in domain _____ and kingdom _____. Part E: In the five-kingdom system, which kingdom consists primarily of unicellular eukaryotes? Part F: In the two-kingdom system, why were fungi classified in the kingdom Plantae? Part G: There is(are) _____ eukaryotic domain(s).
Part A: Bacteria and Archaea Part B: Monera Part C: Eukarya ... Animalia Part D: Eukarya ... Plantae Part E: Protista Part F: They are sedentary. Part G: one
Current Events: The Trials of Stem Cell Therapy (New York Times, 9/15/2014) Part A: Which of the following treatments with stem cells is currently most likely to be effective? Part B: Which of the following is true? Part C: Which of the following is true? Part D: You are part of a research team working on developing a stem cell treatment for amyotrophic lateral sclerosis. What type of cells are you trying to repair? Part E: Your uncle has a stem cell treatment in which he has skin cells injected into his lungs. A benign tumor of skin cells resulted. What is this called?
Part A: Bone marrow transplant. Part B: All cells in the human body can be traced back to an embryonic stem cell. Part C: Your cheek cells contain the same DNA as your brain cells. Part D: nerve Part E: a teratoma
Chapter 5 Question 8 Part A: Lysozyme, an enzyme found in human saliva, tears, and other secretions, catalyzes the hydrolysis of the β-1,4-glycosidic linkages in peptidoglycan. Predict the effect of this enzyme on bacteria. Part B: Predict how this enzyme may be involved in human health.
Part A: Lysozyme destroys bacterial cell walls, leading to the death of the bacteria. Part B: Lysozyme helps to protect humans against bacterial infections.
Chapter 6 Question 5 Part A: Cooking oil lipids consist of long, unsaturated hydrocarbon chains. Would you expect these molecules to form membranes spontaneously? Why or why not? Part B: Describe, on a molecular level, how you would expect these lipids to behave in water.
Part A: No, because they have no polar end to interact with water. Part B: Lipids would float on the surface of the water, or collect in droplets suspended in water, reducing their interaction with water to a minimum.
Making Models: Drawing DNA Sequences Part A: Which part of this visual model represents genetic information? Part B: Models of the double helix are good at showing the three-dimensional shape of DNA, but they are not the best type of model to use for comparing DNA sequences. Use the double helix model shown as a reference to finish the easier-to-read DNA sequence model. Part C: Based on this small amount of DNA sequence data, which species do you predict is most closely related to Pink salmon? Draw a model and circle the letter differences to help you derive your answer.
Part A: the sequence of Ts, Gs, Cs, and As Part B: T-G-C-T-T-C-G-A-T-C-T-C-T-G-T Part C: Chum salmon
Making Models: Drawing Nucleotides Part A: Which symbol is generally used to represent a sugar in simple models of nucleotides? Part B: Several students have been practicing drawing their models of nucleotides. Whose model do you think is most consistent with the actual chemical structure of nucleotides? Part C: Interpret the model. Drag "True" or "False" to the end of each statement. Part D: Which chemical structure is represented by the yellow shape in the model? (yellow circle)
Part A: Pentagon Part B: Jamal circle-pentagon-hexagon Part C: The 3' and 5' carbon labels are in the correct locations in the model. True This model shows that there is more than one kind of sugar. False This model shows that phosphate groups bond to sugars. True This model represents two nucleic acids bonded together. False This model shows six nucleotides bonded together. False This model shows that there is more than one kind of nitrogenous base. True This model shows that phosphate groups bond to nitrogenous bases. False Part D: O II O-P-O I O
Chemistry Review - Water: Properties of Water Part A: Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface? Part B: Dissolving is best described as ... Part C: Water is a source of ______________ for chemical reactions in cells. Part D: Which statement is true of water's tensile strength? Part E: Water has surface tension because ... Part F: Which of the following helps most to explain why water has a high specific heat? Part G: Which factor is important in making it possible to cool yourself by sweating? Think carefully! Part H: Though you add heat, the temperature of boiling water remains constant because ... Part I: Which statement helps to explain why ice is less dense than liquid water? Part J: The open spaces in water's crystal structure make it possible for ... Part K: Why doesn't oil mix with water?
Part A: Polar groups attract one another. Part B: a mingling of molecules and/or ions. Part C: Both (a) and (b) (a)=hydrogen atoms (b)=oxygen atoms Part D: (a), (b), and (c). (a)=It results from hydrogen bonding. (b)=It helps to pull water through plants. (c)=It involves both cohesion and adhesion. Part E: hydrogen bonds between surface water molecules resist being stretched. Part F: (a) A water molecule can make 4 hydrogen bonds. Part G: Both (a) and (b). (a)=Molecules collide with varied angles and speeds. (b)=Hydrogen bonds are relatively weak. Part H: it takes energy to break hydrogen bonds. Part I:Both (a) and (b). (a)=Water molecules make hydrogen bonds at definite angles. (b)=Cold molecules move less than warm molecules. Part J: (a) aquatic life to exist at the North Pole. Part K: (c) Polar molecules attract one another.
Chapter 6 Question 12 - Case Study Part A: How is the chemical structure of saturated fats different from that of unsaturated fats? Part B: What physical property is often associated with these chemical differences?
Part A: Saturated fats have fatty acid tails with only C−C bonds while unsaturated fats have one or more C=C bonds in the tails. Part B: C=C bonds normally result in kinks that increase the spacing between fats and thus make unsaturated fats more fluid than saturated fats.
Osmosis Part A: A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? Part B: A semipermeable membrane is placed between the following solutions. Which solution will increase in volume? Part C: A red blood cell has been placed into three different solutions. One solution is isotonic to the cell, one solution is hypotonic to the cell, and one solution is hypertonic to the cell. Determine which type of solution is in each beaker based on the cell's reaction. Drag each item to the appropriate bin. Part D: A red blood cell placed in a hypertonic solution will shrink in a process called crenation. A red blood cell placed in a hypotonic solution will swell and potentially burst in a process called hemolysis. To prevent crenation or hemolysis, a cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl or 5.0% (m/v) glucose. This does not mean that a cell has a 5.0% (m/v) glucose concentration; it just means that 5.0% (m/v) glucose will exert the same osmotic pressure as the solution inside the cell, which contains several different solutes. A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. Solution A: 3.21% (m/v) NaCl Solution B: 1.65% (m/v) glucose Solution C: distilled H2O Solution D: 6.97% (m/v) glucose Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl Drag each solution to the appropriate bin.
Part A: Solution A: 1.4% (m/v) starch Part B: Solution D: 12.4% (m/v) NaCl Part C: Hypertonic- spikey red ball Isotonic-Red ring Hypotonic- red ring being popped Part D: Crenation-D, A, E Hemolysis-B, C Neither- None
Activity: Exocytosis and Endocytosis Part A: Endocytosis moves materials _____ a cell via _____. Part B: You can recognize the process of pinocytosis when _____. Part C: A white blood cell engulfing a bacterium is an example of _____.
Part A: into ... membranous vesicles Part B: the cell is engulfing extracellular fluid Part C: phagocytosis
Activity: Heritable Information: DNA Part A: DNA is composed of building blocks called _____. Part B: In eukaryotic cells DNA has the appearance of a _____.
Part A: nucleotides Part B: double helix
Activity: Osmosis and Water Balance in Cells Part A: What name is given to the process by which water crosses a selectively permeable membrane? Part B: This cell is in a(n) _____ solution cytoplasm shrinks, extracellular fluid gets larger Part C: You know that this cell is in a(n) _____ solution because the cell _____. Part D: You know that this cell is in a(n) _____ solution because it _____.
Part A: osmosis Part B: hypertonic Part C: hypotonic ... swelled Part D: hypertonic solution ... lost water
Activity: Build a Chemical Cycling System Part A: What process occurs in structure H? Part B: What molecules belong in space A and B? Part C: What organelle is indicated by the letter C? Part D: What molecules belong in spaces E and F?
Part A: photosynthesis Part B: glucose and oxygen Part C: mitochondrion Part D: carbon dioxide and water
Current Events: Young Blood May Hold Key to Reversing Aging (New York Times, 5/4/2014) Part A: Which of the following appears to be most critical when it comes to keeping essential tissues active and vital? Part B: Which of the following is true? Part C: Which of the following is true? Part D: If current research holds true, which of the following people are most likely to benefit from these findings? Part E: You are a scientist researching the human version of GDF11. Assuming this protein is found in the same tissue as in mice, where do you obtain it?
Part A: stem cells Part B: Parabiosis has positive effects on one of the animals involved and negative effects on the other. Part C: GDF11 has the potential to impact multiple body systems. Part D: people over 75 Part E: blood
Making Models: Drawing Flow Charts--Cellular Respiration Part A: Alfred has drawn a flow chart to show a time sequence of four processes of cellular respiration. Which sequence of three labels is the best choice to finish his model? Part B: Corinne has drawn a flow chart to track the fate of carbons during cellular respiration. Interpret her model. Part C: Maria has drawn a flow chart using stars to track electron carriers (NADH and FADH2) during cellular respiration, but she hasn't completed her model. If twelve electron carriers are delivered to the electron transport chain (ETC) per molecule of glucose, how many stars should she show being produced during glycolysis and pyruvate processing? Part D: David has drawn a flow chart to track the ATP inputs and outputs in cellular respiration per molecule of glucose entering glycolysis. According to David's model, how many ATP are gained overall? Part E: Yuki has drawn a flow chart to track the major inputs and outputs in cellular respiration. Select the most suitable set of labels for the numbered arrows.
Part A:glycolysis / pyruvate processing / citric acid cycle Part B: Both the red circles and the orange circles represent carbons. True The missing label for the bottom pair of arrows should be "Electron transport chain." False The model shows that the number of carbons decreases over time. False The orange circles represent the carbons in CO2. True Each pyruvate molecule yields one 2-carbon acetyl CoA and one CO2. True The horizontal lines represent covalent bonds between carbons. True Part C: 2 stars + 2 stars Part D: 29 ATP Part E: 1. produces 2. produces pyruvate used in 3. transfers electrons to
Which of the following is a covalent modification that can affect enzyme activity?
Phosphorylation
Compare and contrast polysaccharides and nucleic acids in terms of monomer diversity and how the monomers are joined together. Drag the appropriate items to their respective bins.
Polysaccharides- monomers vary extensively linkages vary widely in geometry monomers vary in the orientations of hydroxyl groups linkages vary widely in location Nucleic Acids- there are only four different monomers
You believe a bacterium is attaching to animal cells by binding to the carbohydrate portion of a specific glycoprotein. To test this hypothesis you pre-incubate the bacteria with various molecules and then test for inhibition of attachment to the animal cells. Which result supports the hypothesis that the bacteria recognize the carbohydrate component of the animal glycoprotein? See Section 5.3 (Page 114) .
Pretreatment with the carbohydrate component alone prevents bacteria attachment to the animal cells.
Which of the following statements about protein primary structure is true? See Section 3.2 (Page 84).
Primary structure is produced by the unique sequence of amino acids in a protein.
Why does relative enzyme activity shown in Figure 8.15a appear to drop off, when other studies have shown that reaction rates tend to increase at higher temperatures? See Section 8.4 (Page 183) .
Protein denaturation
In the Buchner experiment, why did boiling of the yeast extract prevent the processing of sugar?
Proteins were denatured.
How does a pump differ from a channel or a carrier?
Pumps require energy for transport, but channels and carriers do not use energy.
What is responsible for the decreased stability of RNA compared to DNA?
RNA's secondary structure is less stable because it includes short regions of double helices and looped structures. RNA is less resistant to cleavage because it has a hydroxyl group on the 2' carbon.
As shown in Figure 9.10, citrate is the initial carboxylic acid in the citric acid pathway and oxaloacetate is the final carboxylic acid. To determine if the citric acid pathway was cyclic, Krebs treated cells with radioactive oxaloacetate. What would have been the result of Krebs' experiment if the pathway were linear instead of circular?
Radioactive oxaloacetate + acetyl-CoA would produce no radioactive citric acid cycle intermediates.
Small subunit RNA sequences are useful for building a Tree of Life because _____.
Small subunit RNA sequences are similar in closely related organisms and less similar in less closely related organisms.
For prokaryotic cells, which statement is correct concerning how the structure of a particular cell component correlates with its function? See Section 7.1 (Page 144) .
The cell wall is a tough, fibrous layer that protects the cell and gives it shape and rigidity.
Cellulose, chitin, and peptidoglycan function as structural molecules and withstand pulling and pushing forces well. Which structural feature is most directly responsible? See Section 5.3 (Page 114) .
Structural polysaccharides exist as sets of long, parallel strands that are linked to one another.
What is the significance of the 2' hydroxyl on ribose for RNA function compared to DNA which lacks the 2'?
The 2' OH increases the reactivity of RNA.
What does the species name of Boquila trifoliolata mean? Why is this name appropriate?
The Latin root tri means "three" and foli means "leaf". The name is appropriate because, as the photo shows, the vine consists of clusters of three-part leaves along its length.
How does pH affect enzyme-catalyzed reactions?
The concentration of protons affects an enzyme's folded structure and reactivity.
The functional form of PAH contains four identical active sites, but based on the amino acid sequence of the protein, only one active site can be formed. What does this imply concerning the structure of the functional enzyme?
The functional form PAH consists of four identical protein subunits, each providing one active site.
Proteins are amphipathic molecules that contain nonpolar (hydrophobic) amino acids and polar (hydrophilic) amino acids. Where would you expect to find the hydrophobic and hydrophilic amino acid residues of a transmembrane protein?
The hydrophobic amino acids would come into contact with the hydrocarbon tails of the phospholipid bilayer, whereas the hydrophilic amino acids would interact with the intracellular and extracellular environment.
Which statement best describes the R-groups or side chains of amino acids?
The nature of side chains determines how soluble each amino acid is in water.
Under what conditions could some exothermic (ΔH<0) reactions be nonspontaneous (ΔG>0)? See Section 8.1 (Page 173) .
The overall reaction reduces entropy (products have less entropy than reactants).
Which of the following statements best describes the fluid-mosaic model of membrane structure?
The phospholipid bilayer contains diverse proteins, including some embedded amphipathic proteins that span the bilayer.
If a reaction is exergonic, then which of these statements is true?
The products have lower Gibbs free energy than the reactants.
What occurs during the process of cooking the meat on a grill that would explain this result?
The saturated fat in meat undergoes a change in its physical state as it is heated − from a semisolid consistency to a liquid. When meat is grilled, the liquefied fat drips off, resulting in less saturated fat in the final product.
How could two four-sugar oligosaccharides be structurally different even if both consist of two glucose monomers and two galactose monomers? See Section 5.2 (Page 111)
The sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both).
High-fructose corn syrup is produced by converting starch from corn into a mixture of glucose and fructose monosaccharides. What two events must occur in this process in order to turn starch into these simple sugars?
The starch polymer must be hydrolyzed by an enzyme such as amylase. The second event must be to convert some of the glucose sugars into fructose.
Which of the following scenarios would you predict to be responsible for activating this enzyme?
The sugar is an allosteric regulatory molecule for the enzyme.
How are the structures of RNA and DNA similar? See Section 4.3 (Page 102) .
Their sugar-phosphate backbones are formed by phosphodiester linkages.
Which statement most accurately explains why ATP hydrolysis is highly exergonic? See Section 8.2 (Page 176) .
There is a large drop in potential energy because charge repulsion is reduced
Suppose that the plasma membrane around a eukaryotic flagellum is opened to reveal the axoneme inside. The dynein sidearms between the peripheral microtubule doublets are removed by chemical treatment and ATP is added. What is the expected observation?
There will be no movement, because the ability to use ATP is lost.
hat do myosin, dynein, and kinesin all have in common?
They all hydrolyze ATP to provide energy for movement.
Which of the following is true of membrane lipids? See Section 6.1 (Page 121)
They contain a hydrophilic head group and a hydrophobic tail.
What happens when phospholipids are placed into water?
They form liposomes.
How do the phospholipids in archaea differ from those in other cells?
They have isoprenoid tails instead of fatty acid tails.
What is the significance of buffers in biological systems?
They help maintain homeostasis with respect to pH
What did Linnaeus' system of naming organisms ensure?
Two different organisms never end up with the same genus and species name.
Starting at the 5' end, what is the base sequence of the RNA strand shown in Figure 4.3? See Section 4.1 (Page 95) .
UAGC
Which of the following correctly orders amino acids Asp, Tyr, and Val from most hydrophobic (on the left) to most hydrophilic (on the right)? See Section 3.1 (Page 80) .
Val, Tyr, and Asp
Region A has a low solute concentration. Region B has a high solute concentration. They are separated by a selectively permeable membrane that is impermeable to the solute but allows passage of water. Which of the following is true?
Water moves from region A to region B via osmosis.
When is the overall free energy change ΔG in a reaction most likely to be negative (meaning that the reaction is exergonic)? See Section 8.1 (Page 173) .
When products have lower potential energy and higher entropy than reactants
What two conditions must be present for osmosis to occur?
a membrane that allows only water to pass, but not the solute concentration gradient on the two sides of a membrane
A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____. See Section 7.1 (Page 144) .
a nucleus
The three types of lipids found in cells (fats, steroids, and phospholipids) are insoluble in water because they all possess _____.
a significant component of hydrocarbons
What are the components of a nucleotide? See Section 4.1 (Page 95) .
a sugar, a phosphate group and a nitrogenous base
The linear order of amino acids in a protein helps determine which level of protein structure?
all the levels of protein structure
One of the roles of plasma membrane proteins is to____. See Section 6.4 (Page 131) .
allow passage of select molecules that could not otherwise cross the lipid bilayer
What type of chemical interactions do phospholipids have with their environment?
amphipathic
What two functional groups are bound to the central carbon of every free amino acid monomer?
an amino group and a carboxyl group
What two functional groups are present in every amino acid?
an amino group and a carboxyl group
Cells of which organisms lack cell walls? See Section 5.2 (Page 111) .
animals
A hydrophobic R group would most likely be found _____.
buried in the interior of a protein
Explain how molecular chaperones facilitate protein folding in many different polypeptides, each with their own specific shape.
by preventing unfolded proteins from clumping together
What molecule is produced in the citric acid cycle as a by-product of glucose oxidation and is considered a waste product? See Section 9.4 (Page 198) .
carbon dioxide
What are the primary functions of carbohydrates in cells?
cell identity, energy storage, raw material source for synthesis, and structure
Which of the following cell structures would you expect to be most important in the growth of bacteria in the hypotonic surrounding environment?
cell wall
Which of the following polysaccharides composes the cell wall of fungi? See Section 5.2 (Page 111) .
chitin
If the lipid bilayer were to contain the CFTR molecule, what would pass through the membrane if you added a 1 M solution of sodium chloride on the left side and a 1.5 M solution of potassium ions on the right? Assume that there is an equal amount of water on each side at the start of the experiment. Select all that apply.
chloride ions water will initially move from the right to the left, then backward
An enzyme inhibitor that is roughly the same shape as the substrate and binds at the active site is termed a(n) _____ inhibitor. See Section 8.4 (Page 183)
competitive
During protein synthesis, the peptide bond between amino acids is formed by the process of _____. See Section 3.1 (Page 80) .
condensation
Enzymes speed up chemical reactions by ____. See Section 8.3 (Page 180) .
decreasing the activation energy
Detergents are useful for isolating membrane proteins because____.
detergents are amphipathic
Which of the differences listed here could be found among molecules of the same monosaccharide?
different orientations of a hydroxyl group in the ring form
Redox reactions involve the gain or loss of _____. See Section 8.2 (Page 176) .
electrons
When ATP is hydrolyzed into ADP and inorganic phosphate, _____. See Section 8.2 (Page 176) .
free energy is released
Linnaeus' taxonomic system specifies a unique name for each organism. The first part of the name is the organism's _____, and the second part is its _____.
genus; species
The transmembrane transport protein GLUT-1 transports _____.
glucose
The secondary structure of proteins results because of _____ bonding between atoms in the protein's backbone. See Section 3.2 (Page 84) .
hydrogen
The _____ functional group can always be found in a carbohydrate molecule. See Section 5.1 (Page 109) .
hydroxyl
Where does the citric acid cycle occur in eukaryotes?
in the matrix of mitochondria
Which of the following would decrease membrane fluidity?
increased level of saturation of fatty acids
The lowering of activation energy during the transition step of enzyme catalysis depends on _____ at the enzyme's active site.
interactions with R-groups
For a chemical reaction to proceed spontaneously _____.
it must occur without an input of external energy.
If you were a physician treating a person with this disease, which of the following would you have them exclude from their diet?
lactose
A chemical reaction that proceeds spontaneously ____.
must proceed without an input of external energy
Which type of molecule moves across a cell membrane most easily?
lipid-soluble, nonpolar molecules such as oxygen and carbon dioxide
Integral membrane proteins are anchored in lipid bilayers. Which of the following groups of amino acid residues (see the figure below) would likely be found in the portion that crosses the lipid bilayer?
nonpolar
Which of the following classes of macromolecules always contains a carbohydrate portion? See Section 5.1 (Page 109) .
nucleic acids
Glycoproteins are important in cell-cell recognition. Where are the carbohydrate portions of these molecules normally found?
on the exterior surface of the cell membrane
What type of information is used to direct different polypeptides to fold into different shapes? Select all that apply.
order of amino acids that make up the polypeptide type of amino acids that make up the polypeptide
The sugars found in nucleotides are _____.
pentoses
Modern taxonomy attempts to describe the _____, or genealogical relationships, among organisms.
phylogeny
A large boulder is balanced on top of a hill. You give the boulder a push, and it rolls down the hill. This is an example of converting _____ energy to _____ energy.
potential; kinetic
The bacterial cell wall functions to _______. See Section 7.1 (Page 144) .
protect the cell and provide shape and rigidity
One of the purposes of the citric acid cycle is to _____.
reduce NAD+
Compared to NAD+, NADH is ____.
reduced and has more potential energy
The alpha-helix is a component of __________ protein structure. See Section 3.2 (Page 84) .
secondary
In the figure below, the energetic coupling of ATP hydrolysis and an endergonic reaction are shown. QUANTITATIVE If the hydrolysis of ATP releases 7.3 kcal of free energy, use the graph in this figure to estimate what you would expect the ΔG values to be for the coupled reaction.
step 1 has a ΔG of about -3 kcal/mol and step 2 has a ΔG of about -3 kcal/mol
The extensive hydrogen bonding found among parallel glucose polymers of cellulose enables it to function in plants as a(n) _____.
structural polysaccharide
Nucleotides are joined by a _____ to form the DNA and RNA polymers that function in the cell.
sugar-phosphate linkage
Carbohydrates are important in _____.
supplying sugars found in DNA and RNA
Glycolysis is a series of ___ reactions that occurs in the _____ of cells. See Section 9.2 (Page 194) .
ten; cytoplasm
Starting in the 1960s, newborns that were identified as having PKU were placed on a strict low-protein diet that reduced the effects of PKU on mental impairment. What are other avenues of research that may lead to a cure beyond this restrictive diet? Select all that apply.
the administration of the coenzyme to overcome defects in its production the development of drugs that would help PAH to form the catalytically active conformation
Many proteins fold spontaneously because _____.
the bonds that form secondary and tertiary structure are energetically favorable
The energy for the polymerization of nucleotides comes from____.
the hydrolysis of phosphate groups from nucleoside triphosphates
What is a transition state?
the intermediate complex formed as covalent bonds in the reactants are being broken and re-formed during a reaction
The degree of saturation of phospholipids in a membrane will affect which of the following functions of phospholipids?
the permeability of the membrane
What may have aided the polymerization of amino acids into peptides in the oceans of early pre-biotic Earth?
the presence of mineral surfaces for the amino acids to adhere to
The predominant form of glucose dissolved in an aqueous solution is _____.
the ring configuration
Which of the following parts of an amino acid vary among different amino acids? See Section 3.1 (Page 80) .
the side chain, or R group
A chemical that breaks disulfide bonds might destroy which level of protein structure?
the tertiary structure
Consider a molecule that can diffuse across a lipid bilayer. At equilibrium ____. See Section 6.3 (Page 128) .
there is no change in the concentration of the molecule on either side of the membrane
When a reaction is at equilibrium _____.
there is no net change in the concentration of reactants and products
Polysaccharides probably did not play an important role in the origin of life because ____.
they cannot serve as a template for replication
If you were to expose cells that are undergoing cellular respiration to a radioactive oxygen isotope in the form of O2, which of the following molecules would you expect to be radiolabeled?
water
A reaction will be spontaneous at all temperatures under which set of conditions?
ΔH is negative and ΔS is positive.